This invention relates to a fuel supply system for a heat generator of the kind comprising at least one fuel spray tube disposed in an air inlet tube for the generator, the spray tube being connected to a fuel feed connection in a line supplied with fuel under pressure by a pump having a delivery greater than the fuel consumption rate of the generator, the latter line being connected to the pump output and having downstream of the fuel feed connection a variable-opening throttle element acted upon by control means responsive to the air flow through the inlet tube, the pressure fuel line extending by way of the variable-opening throttle element to a constant-level chamber into which the excess fuel circulated by the pump flows, the pump intake being connected to the constant-level chamber, the control means for the throttle element comprising a moving element forming a movable wall of a chamber experiencing a negative pressure produced by the air flow through a portion of the inlet tube and connecting means between such moving element and the throttle element, the latter means being so devised that the fuel pressure in the spray tube feed line is under the control of the rate of air flow to the generator.
The invention is applicable to heat generators, such as external combustion engines, including burners for steam engine boilers, and to valved and ported internal combustion engines such as 4-stroke or 2-stroke engines and rotary piston engines.
It is an object of the invention to improve the practical performance of such a fuel supply system, inter alia so as to provide improved low-load operation of the heat generator, i.e. to improve the operation thereof when the rate of fuel consumption by the generator is low.